Global warming could lead to additional suicides, new research indicates

A rise in global temperatures is expected to lead to an increase in suicides, new Stanford research suggests.

The correlation between hot weather and a spike in suicides has long been known. But now, researchers led by economist Marshall Burke, PhD, have teased out the effects of temperature from the many other factors affecting suicide rates by comparing historical temperature and suicide data from the U.S. and Mexico. They also correlated the use of depressive language — such as "lonely" — on Twitter with temperature.

The findings, which appear today in Nature Climate Change, are striking and sobering: An additional 21,000 people may die by suicide by 2050 in parts of the U.S. and Mexico due to rising temperatures.

"When talking about climate change, it's often easy to think in abstractions. But the thousands of additional suicides that are likely to occur as a result of unmitigated climate change are not just a number, they represent tragic losses for families across the country," Burke said in a Stanford news release.

The researchers found the rates did not change based on population wealth or whether the hot weather was usual in a particular region. They also emphasized that rising temperatures are not direct motivations for suicide, but that the temperature can increase the chance that a situation results in self-harm.

"Hotter temperatures are clearly not the only, nor the most important, risk factor for suicide," Burke said in the release. "But our findings suggest that warming can have a surprisingly large impact on suicide risk, and this matters for both our understanding of mental health as well as for what we should expect as temperatures continue to warm."

Individuals in crisis can receive help via Crisis Text Line (text HOME to 741741) or the National Suicide Prevention Lifeline at (800) 273-8255. These services are free, confidential, available anywhere in the United States and available 24 hours a day, seven days a week.